CSF2 and hand, foot and mouth disease: Although some reports indicate that serum levels of cytokines, such as IL-2, IL-4, IL-10, IFN-γ, GM-CSF, and TNF-α, may be independent risk factors for early medical intervention [7, 8], at present there are no reliable and easily-operated biomarkers that could be used to assist diagnosis of HFMD in clinical practice.